Grip pulley



-I L. K. DAVIS.

GRIP PuLLEv'. APBLICATlON FILED JUNE l2I 1,922.

mmm im 1w; 1922,.,

' `Vrlhis invention relates to sectional Patented Oct. 10, 1922.

immagini 4 UNITED SEMES PATENT 9 EWE] Lewis Devis, QE Weeilierondiisrmcm or CQLUMBIA.

@R112 BULLEY,

Application felled June 12, 1922. Serial No. 567,847,

To all whom t may concern.'

Be it known that I, LEWIS K. DAVIS, a citizen ofthe United States', residing' in Washington,'District of Colui'nbia,` have invented certain new and useful'k Improvements i Grip Pulleys' tre@ the temine speci'cation." l

belt pulleys of' the :lindfinvvliichj piovieion ijs made fort rmlygripping"the-belt With` which the pulleyis Vaeslociat'ed"when there is a tendencyv for the'latterito slipl onft-h'e i'ormerfor yvhere lthe pulley runsfahead of the belt, and the obj ect'of the inventionis to providev means lwhen the belt starts to slip it will be automatically 'gripped and carried forward Without appreciable lost motionl i "Brieiiy stated, the invention consists in providing vmeans vvhereby'V Whenthe' belt starts to slip` 'Willjcau'se"one of the pulley section'sjto automatically move toward the other, 2orthye gripping sections or members to be simultaneously" movedtoWard each other insuchmanner as to 'cause the grip-f members tof quicklygrasp the'bel-t v4so that the "la'tter is driven forward Without dela l Mere specifically, the invention consists in provding'threepnlley sectionsgtwooi" which have gripping;c members Yengiaging ithe belt @devoting wehrte axle ed a wird' of` interniediateV section vvhichis loose" on the axle `but `frictitmal-v engagement with the belt and?" moves coincidentally "therewith: The arrangement is suchthat when the belt Startseite slip, the movement of thethirdor l intermediate edition-isv ifetarded and certainV devices connecting the sections are brought into action which immediatelycause thebelt to be lfirmly graspedi the mem bers and movediorward inthe normal ivay. Preferably 'the' `pulley,l in its` most` "approved y'fornn' 'comprises two gripping sections` mounted to :turn uvvithl a centrally arf rangedaile and adjustable endvvise "of the aigle f 'and af thirdj sectionmo'untd iturn 'on the axle or `about the axis'thereofgbuthaving its peripheryfin engagement' vvith Ytlie belt v1so' thatA it normally inoies'coiincidenl tally vvitlithe gripping sections". Thehubs Oibees @fthe theeescagpjshave threads? connections with each other so constructed that When the belt startsto slipv the grippingmenibers4 are made to grasp the belt in thenanner before explained.

In the accompanying drawings Fig-ure l isfa View m' vertical section of i Parts of a grip-pulley embodying myinven portion ,.1 y

" F ifur'e 7 is a detail perspective viewsho`W- ing t e screw Atli'readed connections between the pulley sectionsfin thel form oi 'pulley shown Figure 1f Y F igure 8 isa detail view illustrating the cams'forming part of the modified constructionshown in Figure 5.y f"

The pulley mf be employed in various Waysand for ditierent purposes. For convenience 'I-have herein show-n it as applied to a belt or"en`dles`s track such as isconfbl monly used intractors and similar vehicles. The manner in vvhich the pulley `or pulleys A may be associated with anendless belt- B is indicated in Figure' 2Q fkThebelt as shown in Figures 1, 2 and 3 isl formed With acentrally arranged rib or ange b which'is preferably;y though not necessarily,`taperedl Instead "of employing a continuous ribl l may'use aA broken rib or series of teeth b* as indicated'vinr Figure 4. The belt is made of ieXible material, such as rubber or rubber combined lWith canvas or other usual mate# rials.` i"

The Xpulley shown is madein three sections Y ancl'Z; The sections X and Z are keyed tothe laxle C,`Whi1e the intermediatesection Yis loose on the axle. Breferablyy the axle C is mounted to 'revolvein ball bearings D and it is grooved Vat o, '0" to -receiveiinternal ribs on'the hubs `or bosses of'tliesections X and Z.

" The section'Y iS"placedbetween the sections' X `and Z and has a bushing y tted to the axle C so as to turn freely thereon. The sections X and Z are formed at their outer ends or peripheral portions with gripping members a: and .e adapted to grasp the rib b of the belt and with flanges w, a which malte contact with the inner side oi the belt B.

The periphery y of the intermediate section Y makes contact with the inner portion oi' the rib b so that when the belt is moved, the section Y is revolved about the axis of the axle C.

The sections X and Z have inwardly ex; tending annular flanges d which are screw threaded as shown and engage corresponding threads on the hub c of the section Y. Right and lett hand threads are employed and the arrangement is such thatl when the section Y moves relatively to the sections X and Z or when the sections X and Z run ahead ofthe belt, the gripping sections will be moved towards each other and the rib of the belt will be grasped by the gripping members and thereafter the belt will move forward with the pulley sections in the nor'- mal way. This operation is practically instantaneous and there is no appreciable lost motion in the operation of the mechanism.

It in the operation of the pulley the belt starts to slip on the flanges av', a', the intermediate section Y will be retarded in its .movement and owing to this relative movement, the screw threaded devices will operate to cause the gripping sections to grasp the belt instantly and cause it to move forward in the normal way with the pulley.

Instead of both sections X and Z being made movable endwise of the axle one only of the sections need be thus moved relatively to the other. The axle C is properly shouldered as indicated to receive the various sections of the pulley and when assembled in the manner shown in Figure l they may be held in place by a nut M and washer N or by other suitable devices. D

A somewhat similar result may be obtained by the construction illustrated in Figures 5 and 6. Where the parts are similar to those shown in Figure l they are similarly lettered. In this case, cam rings F are bolted to the section Y which co-operate with similar cam rings G bolted to the sections X and Z. When the sections X and Z slip under the belt and the section Y is thus retarded, the relative movement will cause the cam ring G to ride on the cams F and the sections X and Z will be drawn toward each other in such manner as to cause the rib b on the belt to be grasped by the gripping members in the manner before described. 'I

I claim as my invention .1.. A grip pulley adapted to be associated with a belt and comprising a plurality of sections at least one of which is mounted to revolve at all times with a centrally arranged axle and another section mounted to turn about a fixed axis independently of the axle while engaging the belt, and means connect-` ing the sections tor causing them to grip the belt when the latter slips on the axle driven section. Y

2. A grip pulley adapted to be associated with a belt having a rib or flange on its inner side and comprising two sections engaging the inner side of the belt on opposite sides of the rib and at least one of which is adapted to revolve at all times with a centrally arranged axle and a third section mounted to turn independently of the axle while engaging the rib of the belt and means connecting the sections for causing them to grip the Lbelt when the latter slips on the axle driven section.

3. A grip pulley adapted to be associated with a belt and comprising two sections mounted to revolve about the axis of a cen trally arranged axle and at least one of which is mounted to revolve at all times with the axlel and another section engaging the belt arranged between the others, mounted to turn independentlyof the axle about a fixed axis while engaging the belt, and means con necting the sections for causing them to grip the belt when the latter starts to slip upon the axle driven section.

4f. A rip pulley adapted to be associated with a elt and comprising a plurality of sections, at least one of which is mounted to revolve at all times with a centrally arranged axle, a third section interposed between the others, engaging the belt and which is adapted to turn about the axis of the axle independently of the other sections, and a threaded connection between the several sections for causing the belt to be gripped by the sections when the belt starts to slip on the axle driven section.

5. A grip pulley adapted to be associated with a `belt and comprising a plurality of sections, at least one of which is mounted to revolve at all times with a centrally arranged axle and another section mounted toturn independently of the axle while engaging the belt, and a right and left hand threaded connection between the sections operated by the belt for automatically causing them to grip the belt when the latter starts to slip on the axle driven section.

6. A grip pulley associated with a belt and comprising two sections mounted to revolve about the axis of a centrally arranged axle and one of which is movable endwise of the .axle toward the other to cause the gripping parts to grasp thev belt, another pulley sec-V tion interposed between-the others engaging the belt kand mounted to turn'on the axle about a ixed axis, and means connecting the several sections for moving the gripping members into firm engagement with the belt.

7. Agrip pulley` associated with a belt and comprising two sections mounted to revolve about the axis of a oentrally arranged axle and one of which is movable endwise of the axle toward the other to cause the gripping members to grasp the belt, another pulley section engaging the belt interposed between the others and mounted to turn on the axle, and a threaded connection between the seotions for movingthe gripping members into rm engagement With-the belt.

8.1A grip pulley adapted tobe associated with a belt and comprising two sections mounted to revolve about the' axis of a centrally arranged axle and one of which is movable endwise of the axle to cause the gripping members to grasp the belt, another pulley section interposed between the others and having a threaded hub engaging a threaded part of at least one of the other sections.

9. A grip pulley adapted to be associated with a belt having a rib or flange on its inner side comprising two sections engaging the inner side of the belt and engaging opposite sides of the rib and at least one of which is adapted to revolve at all times with a oentrally arranged axle and a third section mounted to turn independently of the axle about a lixed axis While engaging the belt rib, and means connecting the sections for causing them to grip the belt when the latter slips upon the axle driven section.

In testimony whereof, I have hereunto subscribed my name.

LEWIS K. DAVIS. 

